Second harmonic generation SHG Experimental Setup Second harmonic Generator of Ba,NaNbso v 694 KDP crvstal Frequency Doubling Tripling etc. Nd-YAG O3 =0,to CO, laser 266m Not all frequencies are generated; phase Nd: YAGi lase matching condition is required 532mm nonlinear Nonlinear Optics such as refractive index, absorption coefficient, etc; Principle of superposition holds! The frequency of light cannot be altered by passing Light cannot interact with light! .At high intensity light nonlinearity phenomena observed! t the interaction (not free space)! P nodified the medium= in turn modify another e Laser beam enters quartz crystal as red light and emerges field or even the original field itself. as blue light(a second order NLO effect: second harmonic generation)9 Polarizers Lenses w SHG Experimental Setup Second Harmonic Generation KDP crystal Ruby laser w 694 nm 2w 347 nm Ti:Sapphire laser l=700 -920nm tp=100fs Pav=400mW RG-Filter Sample Rotation Table U G-Filter Iris PMT Prism 2w @ 3eV Second Harmonic Generator of Ba2NaNb5O15 Frequency Doubling / Tripling etc. Proustite crystal w3 = w2+w1 0.96 mm Nd3+:YAG 1.06 mm CO2 laser 10. 6 mm Not all frequencies are generated; phase matching condition is required Assumption of linearity of the optical medium Þ Optical properties are independent of light intensity, such as refractive index, absorption coefficient, etc; Principle of superposition holds! The frequency of light cannot be altered by passing through a medium. Light cannot interact with light! At high intensity light Þ nonlinearity phenomena observed! Nonlinearity originates from the interaction of light via the medium only (not free space)! Presence of light modified the medium Þ in turn modify another optical field or even the original field itself. Nonlinear Optics Laser beam enters quartz crystal as red light and emerges as blue light (a second order NLO effect: second harmonic generation)